diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfb8372..93f6fb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
+2021.10.23
 - add user pref filters for periods list
+- add user pref columns for periods list
+- add period columns to posts list and user pref
 - fix auto-link to blog pref
+- fix halfday period
 
 2021.09.02
 - update php headers to phpdoc style
diff --git a/README.md b/README.md
index 8dce2f8..ac2cc70 100644
--- a/README.md
+++ b/README.md
@@ -43,9 +43,15 @@ to link this post to a period.
 
 You can also add or remove period to multiple posts from posts actions page.
 
-## MORE
+## LINKS
 
- * License : GNU GPL v2
+ * License : [GNU GPL v2](https://www.gnu.org/licenses/old-licenses/lgpl-2.0.html)
  * Source & contribution : [GitHub Page](https://github.com/JcDenis/periodical)
  * Packages & details:  [Dotaddict Page](https://plugins.dotaddict.org/dc2/details/periodical)
- * Discuss & help: [Dotclear Forum](https://forum.dotclear.org/viewtopic.php?id=42289)
\ No newline at end of file
+ * Discuss & help: [Dotclear Forum](https://forum.dotclear.org/viewtopic.php?id=42289)
+
+## CONTRIBUTORS
+
+ * Jean-Christian Denis
+
+ You are welcome to contribute to this code.
\ No newline at end of file
diff --git a/_define.php b/_define.php
index ba49132..aa04c06 100644
--- a/_define.php
+++ b/_define.php
@@ -19,15 +19,15 @@ $this->registerModule(
     'Periodical',
     'Published periodically entries',
     'Jean-Christian Denis and contributors',
-    '2021.09.02.1',
+    '2021.10.23',
     [
-        'requires' => [['core', '2.19']],
+        'requires'    => [['core', '2.20']],
         'permissions' => 'usage,contentadmin',
-        'type' => 'plugin',
-        'support' => 'https://github.com/JcDenis/periodical',
-        'details' => 'https://plugins.dotaddict.org/dc2/details/periodical',
-        'repository' => 'https://raw.githubusercontent.com/JcDenis/periodical/master/dcstore.xml',
-        'settings' => [
+        'type'        => 'plugin',
+        'support'     => 'https://github.com/JcDenis/periodical',
+        'details'     => 'https://plugins.dotaddict.org/dc2/details/periodical',
+        'repository'  => 'https://raw.githubusercontent.com/JcDenis/periodical/master/dcstore.xml',
+        'settings'    => [
             'blog' => '#params.periodical_params'
         ]
     ]
diff --git a/inc/lib.index.pager.php b/inc/lib.index.pager.php
index 4706e14..8924f22 100644
--- a/inc/lib.index.pager.php
+++ b/inc/lib.index.pager.php
@@ -24,7 +24,6 @@ class adminPeriodicalList extends adminGenericList
 {
     public function periodDisplay($filter, $enclose_block='')
     {
-        $echo = '';
         if ($this->rs->isEmpty()) {
             if ($filter->show()) {
                 echo '<p><strong>' . __('No period matches the filter') . '</strong></p>';